The technical scope of the invention is that of active protection devices for a wall, notably of a vehicle wall.
We know, notably by patent FR-A-2,436,361 a (so-called reactive) protection device that is intended to be fastened to the outer wall of an armored vehicle. This device comprises a sheet of explosive placed between two metallic plates.
When the jet of a shaped charge impacts on the outer metallic plate, the explosive it contains is ignited. Its detonation cause the metallic plate to be projected outwards towards the jet, thereby consuming it and hence reducing its piercing capability. Such a type of armor is not effective enough against APFSDS projectiles or against cores generated by explosively-formed projectiles.
Indeed, as far as the APFSDS projectiles are concerned, the time of interaction between the projected plate and the projectile is much too short for the piercing capability of the projectile to be sufficiently reduced.
With respect to explosively-generated cores, more often than not the cores pass through the reactive armor without igniting the explosive.
Solutions are sought to overcome such drawbacks.
Thus, patents FR-A-2,730,805 and FR-A-2,679,022 propose the combination of reactive armor with a device to detect the onset of the projectile. The plate is projected onto the projectile before it has impacted the armor. The disturbance to the projectile is thus much greater.
However, such armors have further drawbacks. The protective modules are firstly too heavy since they implement substantial masses of explosive and multiple armor plates.
It is therefore not possible to ensure the protection of light vehicles using such devices, nor is it possible to protect tank turrets against attacks from the roof. Nor are these devices able to be used to ensure protection against explosively-formed projectiles.
Indeed, the detection of the onset of the core is very complicated because of its small dimensions (length less than 120 mm, diameter less than or equal to 40 mm).
Reactive armor known by patent FR-A-2,436,361 is more particularly intended for protection against shaped charges. However, they are presently ineffective against so-called tandem charges (described, for example, by patent FR-A-2,577,037). Indeed, these charges incorporate a main rear charge associated with a small front charge whose purpose is to ignite the reactive armor before the arrival of the rear charge, or else to pierce a hole in the reactive armor without igniting it thereby allowing the jet from the main charge to pass through without disturbance.